Sheet metal positioning assembly for use with a sheet metal brake

ABSTRACT

An assembly for positioning sheet metal on a sheet metal brake includes a coarse adjustment mechanism and a fine adjustment mechanism for respectively setting approximate and accurate positions of the sheet metal. Preferably, a mounting structure is removably mountable on front and rear beams of the brake via a pair of respective clamping mechanisms connected to respective mounting legs extending from a hollow tube. One mounting leg is movably connected to the tube for adjusting spacing between the mounting legs to facilitate mounting on the beams. A support arm is slidably received by the hollow tube to provide coarse adjustment. The support arm includes an upwardly extending portion on which is disposed a shelf for supporting an edge of the sheet metal. A threaded member threadably engages the upper portion of the support arm to finely adjust the position of the shelf and piece of sheet metal.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates generally to a sheet metal brake for bending sheet metal. More particularly, the invention relates to an assembly for setting the position of a piece of sheet metal on such a brake. Specifically, the invention relates to such an assembly having a sheet metal-engaging member which is adjustable with a coarse adjustment mechanism and a fine adjustment mechanism.

2. Background Information

Sheet metal brakes are well known in the industry for the purpose of bending sheet metal. In order to bend the sheet metal at the proper location, it is necessary to make accurate measurements and set the piece of sheet metal in a position in accordance with such measurements on the sheet metal brake. A problem arises in setting the position of the sheet metal on the brake, particularly when only one person is operating the sheet metal brake and even more particularly if the piece of sheet metal is relatively large. It has been found somewhat helpful to use a support arm having a coarse adjustment mechanism whereby the support arm supports an edge of the piece of sheet metal and is able to assist in setting the position of the sheet metal generally in the desired position. However, such a coarse adjustment mechanism by itself is still lacking in order to make the process expeditious.

In addition, many sheet metal brakes have no adjustment mechanism at all. Thus, there is a need for such an adjustment mechanism which can be retrofit onto existing sheet metal brakes and which can be used with stationary or portable brakes.

BRIEF SUMMARY OF THE INVENTION

The present invention provides an apparatus for use with a sheet metal brake having a front and a rear and defining an axial direction extending from the front to the rear, the apparatus comprising a movable sheet metal-engaging member adapted to move in the axial direction when used with the sheet metal brake; the sheet metal-engaging member being adapted to facilitate positioning of a piece of sheet metal on the brake in the axial direction; and a fine adjustment mechanism for moving the sheet metal-engaging member in the axial direction to a desired position.

The present invention also provides a sheet metal-positioning assembly for use with a sheet metal brake, the assembly comprising a mounting structure adapted to mount on the sheet metal brake; the mounting structure including a pair of spaced upwardly extending mounting legs; a mounting mechanism mounted on each mounting leg and adapted to mount the respective leg to the brake; a support arm having an elongated first portion and an upwardly extending portion mounted on the first portion; the elongated first portion selectively movably engaging the mounting structure to provide coarse adjustment of the support arm; a sheet metal-engaging member movably mounted on the upwardly extending portion of the support arm and adapted to facilitate positioning of a piece of sheet metal on the brake at a desired location; and a fine adjustment mechanism mounted on the upwardly extending portion of the support arm for moving the sheet metal-engaging member to a desired position.

The present invention further provides a sheet metal-positioning assembly for use with a sheet metal brake, the assembly comprising a mounting structure adapted to mount on the sheet metal brake; an adjustable member selectively movably engaging the mounting structure; the adjustable member including an upwardly extending portion; a coarse adjustment mechanism to provide coarse adjustment of the adjustable member; a first securing mechanism for selectively securing the adjustable member at a selected position; a sheet metal-engaging member movably mounted on the upwardly extending portion of the adjustable member and adapted to facilitate positioning of a piece of sheet metal on the brake at a desired location; a fine adjustment mechanism mounted on the upwardly extending portion of the adjustable member for moving the sheet metal-engaging member to a desired position; and a second securing mechanism for securing the sheet metal-engaging member at the desired position.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a sheet metal brake with a pair of the adjustable assemblies of the present invention mounted respectively to each end thereof and a piece of sheet metal shown in dot-dash lines.

FIG. 2 is an end elevational view of the sheet metal brake shown in FIG. 1 and shows one of the adjustable assemblies.

FIG. 3 is an exploded perspective view of the assembly of the present invention shown in FIG. 2.

FIG. 4 is a fragmentary sectional view of the fine adjustment mechanism of the adjustable assembly.

FIG. 5 is a fragmentary sectional view showing the front clamping mechanism and the coarse adjustment mechanism of the assembly.

FIG. 6 is a fragmentary sectional view of the rear clamping mechanism.

FIG. 7 is a fragmentary sectional view taken on line 7-7 of FIG. 6.

FIG. 8 is an end elevational view of the sheet metal brake and adjustable assembly showing a piece of sheet metal being initially positioned on the sheet metal brake and on a shelf of the support arm of the assembly.

FIG. 9 is similar to FIG. 8 and shows the support arm being moved along with the piece of sheet metal to set a coarse or approximate position of the piece of sheet metal on the sheet metal brake.

FIG. 10 is similar to FIG. 9 and shows the piece of sheet metal being further positioned by the fine adjustment mechanism.

FIG. 11 is similar to FIG. 10 and shows the clamp bar handle of the sheet metal brake moving to a locked position so that the anvil moves downwardly to clamp the piece of sheet metal in place on the sheet metal brake.

FIG. 12 is similar to FIG. 11 and shows the bending bar handle and bending bar pivoting upwardly to bend the piece of sheet metal.

Similar numbers refer to similar parts throughout the specification.

DETAILED DESCRIPTION OF THE INVENTION

The adjustable assembly of the present invention is indicated generally at 10 in FIGS. 1-3. Assembly 10 is used with a sheet metal brake 12 to set the position of a piece 14 of sheet metal on brake 12 prior to bending piece 14 with brake 12. Piece 14 of sheet metal has a front edge 15.

Brake 12 is rigidly positioned on a stand 16, which may be a permanent or portable structure. Portable stands typically include at least a pair of wheels (not shown) to facilitate mobility of the stand and brake thereon. A variety of stands are known in the art for supporting brakes such as brake 12.

With reference to FIGS. 1-2, brake 12 has a front 18, a rear 20, a first end 22 and a second end 24 in opposed relation to first end 22. Brake 12 has a longitudinal direction extending between first end 22 and second end 24 and an axial direction extending between front 18 and rear 20. Brake 12 includes a front beam 26 and a rear beam 28, each being elongated in the longitudinal direction of brake 12. Brake 12 also includes a plurality of C-castings 30 spaced from one another along the longitudinal direction and each defining a throat 32 for receiving a portion of piece 14 of sheet metal. A pivot arm 34 is pivotally connected to each C-casting 30 whereby pivot arm 34 is pivotable about a pivot 36. An anvil 38 is rigidly mounted on each pivot arm 34 and thus moveable with the pivotal movement of pivot arm 34. Anvil 38 is elongated in the longitudinal direction and includes a bending edge 40 also elongated in the longitudinal direction.

A mechanism 42 for lowering pivot arm 34 and anvil 38 into a clamping position includes a lock bar 44 and a lock bar handle 46 extending therefrom. Lock bar 44 is pivotally connected to each C-casting 30 at a pivot 48 and pivotally connected to each pivot member 34 via pivots 50 and 52. A clamping base 54 is connected to front beam 26 and is disposed below anvil 38. Clamping base 54 is elongated in the longitudinal direction. A bending bar 56 is pivotally connected via a hinge 58 to clamping base 54 and is elongated in the longitudinal direction. A pair of bending bar handles 60 extend from bending bar 56.

In accordance with a feature of the invention and with reference to FIGS. 1-3, assembly 10 is removably mounted to brake 12 as detailed further below, although a permanently mounted assembly is also contemplated. In accordance with another feature of the invention, assembly 10 includes a mounting structure 62 and an adjustable member in the form of a support arm 64 which is selectively moveably connected to mounting structure 62 to allow support arm 64 to extend and retract in the axial direction of brake 12. Mounting structure 62 includes a support arm engaging member in the form of a hollow tube 66 which slidably receives support arm 64. More particularly, tube 66 defines an interior chamber 68 for slidably receiving support arm 64. Tube 66 has a substantially square cross-sectional configuration although a variety of shapes may be used. It is preferred that the cross-sectional shape of tube 66 is non-circular to prevent rotation of support arm 64 within interior chamber 68.

A first mounting member or leg 70 and a rear mounting member or leg 72 spaced from leg 70 each project upwardly from tube 66 and are substantially perpendicular to tube 66. A front clamping mechanism 74 is mounted on leg 70 and a rear clamping mechanism 76 is mounted on rear leg 72. Preferably, front mounting leg 70 includes a lower member or bar 78 extending from and rigidly connected to tube 66 and an upper member or bar 80 adjustably connected to lower bar 78. In the exemplary embodiment, upper member 80 is removably connected to lower member 78 via a fastener such as a threaded bolt 82 and nut 84 with bolt 82 extending through a hole 86 formed in upper bar 80 and a hole 88 (FIG. 5) formed in lower bar 78. Lower bar 78 further defines a hole 90 formed therein and disposed below hole 88 for alternately receiving bolt 82.

Front clamping mechanism 74 is configured to mount front mounting leg 70 to front beam 26 of brake 12 (FIG. 2). Clamping mechanism 74 includes a lower jaw 92 projecting from upper bar 80 and an upper jaw 94 also projecting from upper bar 80 and disposed above lower jaw 92 (FIGS. 2, 3 and 5). Jaws 92 and 94 extend forward with respect to brake 12 and define there between a front throat 95 which opens toward front 18 of brake 12. Thus, a portion of upper bar 80 forms a part of clamping mechanism 74. Clamping mechanism 74 further includes an engaging member in the form of a threaded bolt 96 which threadably engages a threaded hole 98 (FIG. 5) formed in lower jaw 92 in order to secure front leg 70 to front beam 26 of brake 12 via engagement of bolt 96 and front beam 26. In particular, bolt 96 engages front beam 26 from below to engage a lower surface of beam 26 due to the fact that it is far easier to access the space below beam 26 for adjustment than to access the space above front beam 26. However, it is contemplated that a bolt similar to bolt 96 or a similar mechanism may be disposed above front beam 26. Upper jaw 94 of clamping mechanism 74 engages an upper surface of front beam 26 of brake 12 when assembly 10 is mounted on brake 12.

Similar to front leg 70 and with reference to FIGS. 2, 3 and 6, rear mounting leg 72 includes a lower member or bar 100 projecting upwardly from tube 66 and an upper member or bar 102 adjustably connected to lower bar 100. In particular, upper bar 102 is removably connected to lower bar 100 via a fastener in the form of a threaded bolt 104 and nut 106 with bolt 104 extending through a hole 108 (FIG. 6) formed in upper bar 102 and hole 110 formed in lower bar 100. Lower bar 100 further defines a lower hole 112 disposed below hole 110 for alternately receiving bolt 104. This alternate position of bolt 104 in hole 112 and the alternate position of bolt 82 in hole 90 of front leg 70 is used when mounting assembly 10 to a brake with different dimensions than brake 12 and in particular raises support arm 64 to support piece 14 of sheet metal at a proper height for the brake of different dimensions.

Rear clamping mechanism 76 includes a lower jaw 114 and an upper jaw 116 spaced from and disposed above jaw 114, each of jaws 114 and 116 extending from and connected to upper bar 102. Jaws 114 and 116 extend rearwardly with respect to brake 12 and define therebetween a rear throat 117 which opens toward rear 20 of brake 12. Thus, rear clamping mechanism 76 includes a portion of upper bar 102. Mechanism 76 further includes an engagement member in the form of a threaded member 118 having a handle 120 thereon to facilitate rotation of member 118. Threaded member 118 threadedly engages a threaded hole 122 (FIG. 6) formed in upper jaw 116 and engages an upper surface of rear beam 28 of brake 12 when assembly 10 is mounted on brake 12. Unlike front beam 26, it is easier to access the space above rear beam 28 than the space there below. However, a threaded member like member 118 may also engage rear beam 28 from below. Lower jaw 114 of clamping mechanism 76 engages a lower surface of rear beam 28 when assembly 10 is mounted on brake 12.

Referring to FIGS. 3, 6 and 7, rear mounting leg 72 is moveably mounted on hollow tube 66 via an adjustment mechanism 124. In particular, adjustment mechanism 124 includes a moveable member 126 which is in slidable relation with tube 66 to allow the adjustment of spacing between front mounting leg 70 and rear mounting leg 72. In particular, moveable member 126 is slidable in the direction shown by Arrow A in FIGS. 6-7 which is the axial direction of brake 12. Moveable member 126 is a relatively short hollow tube having a square cross-sectional shape although as noted with regard to tube 66, the shape may vary and is preferably non-circular in cross-section. More particularly, moveable member 126 defines an interior chamber 127 (FIGS. 6-7) in which tube 66 is slidably received. Adjustment mechanism 124 further includes a securing or locking mechanism 128 (FIGS. 3 and 7) in the form of a threaded member 130 having a handle 132 to facilitate rotation of threaded member 130. Threaded member 130 extends through a hole 134 (FIG. 7) formed in moveable member 126 so that threaded member 130 is able to selectively engage tube 66 to lock moveable member 126 in a selected position and thereby lock rear mounting leg 72 in a selected position. A lock nut 136 is provided to secure threaded member 130 in place once the position of moveable member 126 has been set. Other adjustment mechanisms analogous to mechanism 124 and securing mechanisms analogous to mechanism 128 will be evident to one skilled in the art.

Assembly 10 further includes a forward securing or locking mechanism 138 (FIGS. 3 and 5). Locking mechanism 138 uses the same concept as locking mechanism 128 and includes a threaded member 140 with a handle 142 thereon to facilitate rotation of member 140. Threaded member 140 threadably engages a threaded hole 144 formed in tube 66 whereby threaded member 140 selectively engages support arm 64 to selectively lock support arm 64 in position. As previously noted, support arm 64 is slidably received within interior chamber 68 of hollow tube 66 and moves in the direction shown by Arrow B in FIG. 5, which is the axial direction of brake 12. Locking mechanism 138 further includes a locking nut 148 (FIG. 5) for locking threaded member 140 in place once the position of support arm 164 is set. Forward locking mechanism 138 is part of a coarse adjustment mechanism 151 (FIGS. 3 and 5) which includes moveable support arm 64. Coarse adjustment mechanism 151 allows for the movement of arm 64 within tube 66 and locking thereof with locking mechanism 138 to quickly provide a coarse adjustment or an approximate position in the process of setting the position of a piece 14 of sheet metal on brake 12.

With reference to FIG. 3, support arm 64 is further described. Support arm 64 includes a substantially straight elongated first portion 150 which is slidably received within interior chamber 68 of hollow tube 66. First portion 150 and hollow tube 66 are each elongated in the axial direction of brake 12 when mounted thereon. Elongated portion 150 has a rear end 152 and a front end 154 opposed to rear end 152. Support arm 64 includes a second portion 156 angling upwardly from front end 154 of first portion 150 on an approximately 45° angle. Support arm 64 further includes a third portion 158 extending generally vertically upwardly from second portion 156.

In accordance with another feature of the invention, a fine adjusting mechanism 160 (FIGS. 3-4) is connected to third portion 158 of support arm 64. Fine adjustment mechanism 160 includes a moveable sheet metal-engaging member 162 which is pivotally connected via a pivot 164 to third portion 158 of arm 64. Moveable member 162 includes an elongated portion 166 in the form of a three-sided channel which extends in a generally vertical direction. Channel 166 defines an interior space 168 within which third portion 158 of arm 64 is received. Moveable member 162 also includes a projection or shelf 170 projecting outwardly from channel 166 in the general direction of mounting structure 62. Elongated portion 166 of moveable member 162 has a generally vertical sheet-metal engaging surface 171 above and adjacent shelf 170 for abutting edge 15 of piece 14 of sheet metal.

Fine adjustment mechanism 160 further includes a threaded member 172 with a handle 174 attached thereto to facilitate the rotation of member 172. Threaded member 172 is threadably engaged with a threaded hole 176 (FIG. 4) formed in third portion 158 of arm 64. The threadable engagement between member 172 and hole 176 allows threaded member 172 to move back and forth in the direction indicated by Arrow C in FIG. 4. A lock nut in the form of a wing nut 178 is provided to selectively secure threaded member 172 in a selected position. Use of wing nut 178 facilitates securing of threaded member 172 into the selected position without the use of tools. The threaded engagement between threaded member 172 and hole 176 provides the fine adjusting aspect of fine adjustment mechanism 160. Preferably, a sleeve 180 is rigidly mounted on elongated member 166 and projects into interior space 168 in a direction generally opposite of shelf 170. Sleeve 180 allows threaded member 172 to rotate relative to sleeve 180 and member 166 and provides a connection between member 172 and elongated member 166 in order to pull member 166 toward third portion 158 of arm 64 as well as push member 166 away from third portion 158. The pivotal movement of elongated member 166 caused by the movement of member 172 is indicated by Arrows D in FIG. 4. Thus, elongated member 166 moves in the axial direction of brake 12 to facilitate positioning piece 14 of sheet metal in said axial direction. Member 166 and shelf 170 are additionally shown in phantom lines in FIG. 4 to further illustrate the pivotal movement thereof. Sleeve 180 may be eliminated although this mechanism facilitates movement of member 166 toward third portion 158 of arm 64 due to the rigid attachment of sleeve 180 to member 166.

To mount assembly 10 on brake 12, front clamping mechanism 74 is positioned to receive front member 26 therein (FIG. 5). The position of rear mounting leg 72 is adjusted as shown by Arrow A in FIG. 6 in order that rear clamping mechanism 76 receives rear beam 28 of brake 12. In a suitable order, locking mechanism 128 is tightened to secure rear mounting leg 72 and rear clamping mechanism 76 in position, bolt 96 is tightened to secure clamping mechanism 74 to front beam 26 and threaded member 118 is tightened to secure rear clamping mechanism 76 to rear beam 28. Another assembly 10, as shown in FIG. 1, is mounted on brake 12 in a similar fashion suitably spaced from the first assembly 10 in order to properly position the piece 14 of sheet metal, as described hereafter.

The operation of assembly 10 and brake 12 is now described with reference to FIGS. 8-12. A piece 14 of sheet metal is positioned as indicated by Arrow E in FIG. 8 between clamping base 54 and anvil 38 and partially into the respective throats 32 of C-castings 30. In addition, front edge 15 of a piece 14 of sheet metal is positioned atop shelf 170.

As shown in FIG. 9, arm 64 is then moved forward and/or rearward within interior chamber 68 of tube 66 as shown by Arrow F to provide a coarse adjustment of the position of sheet metal 14. More particularly, this coarse adjustment positions sheet metal-engaging surface 171 at an approximate position which is a distance D1 (FIG. 9) from bending edge 40 of anvil 38 and which is adjacent or in the rough vicinity of a desired position of surface 171 which is a desired distance D2 (FIG. 10) from bending edge 40, as detailed below. Alternately, arm 64 may be adjusted prior to positioning piece 14 of sheet metal on brake 12 as previously described. When piece 14 is placed on brake 12 prior to making the fine adjustment, it is preferable that the coarse adjustment is made so that piece 14 of sheet metal extends outwardly a bit too far from bending edge 40 of anvil 38 to facilitate making the fine adjustment, although this it not necessary.

FIG. 10 shows fine adjustment mechanism 160 being adjusted to provide a finer and more controlled adjustment of a position of piece 14 of sheet metal in order to provide a more accurate placement prior to the bending thereof. In particular, handle 174 is rotated to rotate threaded member 172 and thereby thread the same in hole 176 to provide forward or rearward movement, as shown by Arrow G in FIG. 10. The movement of threaded member 172 causes moveable member 162 to pivot about pivot 164 forward or rearward as indicated by Arrow H in FIG. 10. This fine adjustment process positions sheet metal-engaging surface 171 at its desired position at desired distance D2 from bending edge 40. Wing nut 178 is then tightened to secure surface 171 at the desired position. By ensuring that edge 15 abuts surface 171 while surface 171 is at its desired position at desired distance D2, piece 14 of sheet metal is thus positioned at a desired location on brake 12. Fine adjustment mechanism 160 is conveniently located to facilitate finely adjusting the position of surface 171 while simultaneously measuring the distance of surface 171 from bending edge 40 with any suitable measuring device. As noted above with regard to making the coarse adjustment, the fine adjustment just described may also be performed prior to placing piece 14 of sheet metal on brake 12. The operation of assembly 10 described with reference to FIGS. 8-10 is also performed with the other assembly 10 (FIG. 1) which is mounted on brake 12. In addition, there may be more assemblies 10 if needed.

Once assemblies 10 have been adjusted to accurately position piece 14 of sheet metal on brake 12, brake 12 clamps piece 14 of sheet metal in place as shown in FIG. 11. More particularly, lock bar handle 46 is moved in a direction shown by Arrow J in FIG. 11 in order to move anvil 38 downwardly as indicated by Arrow K in FIG. 11 to clamp piece 14 of sheet metal between anvil 38 and clamping base 54. As shown in FIG. 12, bending bar handles 60 are then moved upwardly as indicated by Arrow L in order to force bending bar 56 against piece 14 of sheet metal to bend piece 14 of sheet metal as indicated by Arrow M about bending edge 40 of anvil 38.

Thus, assembly 10 provides a simple structure for accurately setting the position of a piece of sheet metal on a sheet metal brake. It will be appreciated that a variety of changes may be made to assembly 10 that are within the scope of the present invention. The broader concept of the present invention is the ability to finely and accurately position the piece of sheet metal on the sheet metal brake. A variety of mechanisms may be used to provide this type of adjustment. For example, the fine adjustment may be provided by a mechanism using engageable gears or rollers. Instead of the pivoting movement sheet metal-engaging member 162, an analogous member may be slidably or rollably mounted on an adjustable member such as support arm 64. Moreover, the assembly need not necessarily include a coarse adjustment mechanism. Indeed, for some applications, the use of a fine adjustment mechanism on a mounting structure without a moveable arm or analogous coarse adjustment mechanism may be suitable. In addition, the various options for moving an adjustable member such as support arm 64 may be suitable as the fine adjustment mechanism without the inclusion of a separate coarse adjustment mechanism. For example, a gear and track combination wherein a tooth gear engages teeth of a flat track to move a member such as support arm 64 may be used in this fashion. An adjustment member such as support arm 64 may also roll on rollers or ball bearings instead of simply sliding within a hollow tube such as tube 66 to facilitate smooth and easy movement. However, assembly 10 provides a simple and inexpensive mechanism for providing the coarse and fine adjustment mechanisms. In general, it is preferred to have both the fine and coarse adjustment mechanisms so that the coarse adjustment mechanism can quickly set the approximate location of the adjustable member and the fine adjustment mechanism can then accurately set the position of the sheet metal with relatively minor adjustment.

As previously discussed, mounting members 70 and 72 are vertically adjustable to allow assembly 10 to be used with sheet metal brakes having different dimensions. More particularly, this allows support arm 64 and shelf 170 to be set at the proper height for placement of the sheet metal thereon and would typically make the top of shelf 70 approximately the same height as the clamping base 54 or analogous structure on another sheet metal brake. The vertical adjustment of mounting members 70 and 72 is provided by a pair of holes in the respective lower members 78 and 100 such that bolts 82 and 104 may respectively be received in these lower holes to adjust the height of arm 64 and shelf 170 upwardly. This vertical adjustment can be done by any other suitable means. For instance, instead of a pair of holes in the lower members, an elongated slot may be used. The use of the pair of holes in the exemplary embodiment is due to the fact that there are currently two primary manufacturers of sheet metal brakes in the United States, each a manufacturer using standard dimensions which differ from one another.

Assembly 10 is configured to mount on the sheet metal brake itself and in particular, on the front and rear beams thereof. However, it is contemplated that the assembly may be mounted on other portions of the sheet metal brake, such as the C-castings or alternately on the stand on which the sheet metal brake sits. It is nonetheless most preferable to have the assembly connected directly to the sheet metal brake, as this provides a simpler and more sturdy connection for the assembly. Other changes may be made to the present invention that would be recognized by one skilled in the art.

In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.

Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described. 

1. An apparatus for use with a sheet metal brake having a front and a rear and defining an axial direction extending from the front to the rear, the apparatus comprising: a movable sheet metal-engaging member adapted to move in the axial direction when used with the sheet metal brake; the sheet metal-engaging member being adapted to facilitate positioning of a piece of sheet metal on the brake in the axial direction; and a fine adjustment mechanism for moving the sheet metal-engaging member in the axial direction to a desired position.
 2. The apparatus of claim 1 further including a coarse adjustment mechanism for moving the sheet metal-engaging member in the axial direction to a position adjacent the desired position.
 3. The apparatus of claim 2 wherein the coarse adjustment mechanism includes an adjustable member adapted to move in the axial direction when used with the sheet metal brake; and wherein the sheet metal-engaging member is movably mounted on the adjustable member.
 4. The apparatus of claim 3 wherein the fine adjustment mechanism includes a threaded member which threadably engages the adjustable member to move the sheet metal-engaging member.
 5. The apparatus of claim 4 wherein the sheet metal-engaging member is pivotally connected to the adjustable member.
 6. The apparatus of claim 3 further including a mounting structure adapted to mount on the sheet metal brake; and wherein the adjustable member is movably mounted on the mounting structure.
 7. The apparatus of claim 6 wherein the adjustable member includes an elongated portion which in use with the brake is elongated in the axial direction; wherein the adjustable member includes an upwardly extending portion mounted on the elongated portion and having an upper end; and wherein the sheet metal-engaging member is movably mounted on the upwardly extending portion adjacent the upper end thereof.
 8. The apparatus of claim 7 wherein the elongated portion of the adjustable member selectively slidably engages the mounting structure.
 9. The apparatus of claim 8 wherein the mounting structure defines an interior chamber within which the elongated portion of the adjustable member is selectively slidably received.
 10. The apparatus of claim 1 further including a structure adapted to be positioned in fixed relation with respect to the sheet metal brake while in use therewith; and wherein the sheet metal-engaging member is movably mounted on the structure.
 11. The apparatus of claim 10 wherein the structure is adapted to be removably mountable on the brake.
 12. The apparatus of claim 10 wherein the structure is adapted to mount on the sheet metal brake.
 13. The apparatus of claim 12 wherein the structure includes at least one mounting mechanism adapted to mount on the brake.
 14. The apparatus of claim 13 wherein the at least one mounting mechanism includes a clamping mechanism adapted to clamp to the brake.
 15. The apparatus of claim 13 wherein the at least one mounting mechanism includes first and second mounting mechanisms which are movable with respect to one another in the axial direction to selectively adjust spacing between the first and second mounting mechanisms.
 16. The apparatus of claim 12 wherein the structure includes a pair of mounting members adapted to mount on the brake; and wherein each of the mounting members is vertically adjustable to adjust the height of the sheet metal-engaging member.
 17. The apparatus of claim 12 wherein the structure is adapted for mounting on spaced front and rear elongated beams of the sheet metal brake.
 18. The apparatus of claim 17 wherein the rigid structure includes a front mounting member adapted for mounting on the front beam and a rear mounting member adapted for mounting on the rear beam.
 19. The apparatus of claim 18 wherein spacing between the front and rear mounting members is adjustable whereby the structure is adapted to generally align the front and rear mounting members respectively with the front and rear beams.
 20. The apparatus of claim 19 wherein a front clamping mechanism is mounted on the front mounting member and a rear clamping mechanism is mounted on the rear mounting member; wherein the front clamping mechanism has a front throat adapted to open toward a front of the brake with the front beam of the brake receivable therein; and wherein the rear clamping mechanism has a rear throat adapted to open toward the rear of the brake with the rear beam of the brake receivable therein.
 21. The apparatus of claim 1 wherein the sheet metal-engaging member is vertically adjustable whereby the sheet metal-engaging member is adapted to engage the piece of sheet metal at a height suited to dimensions of the sheet metal brake.
 22. A sheet metal-positioning assembly for use with a sheet metal brake, the assembly comprising: a mounting structure adapted to mount on the sheet metal brake; the mounting structure including a pair of spaced upwardly extending mounting legs; a mounting mechanism mounted on each mounting leg and adapted to mount the respective leg to the brake; a support arm having an elongated first portion and an upwardly extending portion mounted on the first portion; the elongated first portion selectively movably engaging the mounting structure to provide coarse adjustment of the support arm; a sheet metal-engaging member movably mounted on the upwardly extending portion of the support arm and adapted to facilitate positioning of a piece of sheet metal on the brake at a desired location; and a fine adjustment mechanism mounted on the upwardly extending portion of the support arm for moving the sheet metal-engaging member to a desired position.
 23. A sheet metal-positioning assembly for use with a sheet metal brake, the assembly comprising: a mounting structure adapted to mount on the sheet metal brake; an adjustable member selectively movably engaging the mounting structure; the adjustable member including an upwardly extending portion; a coarse adjustment mechanism to provide coarse adjustment of the adjustable member; a first securing mechanism for selectively securing the adjustable member at a selected position; a sheet metal-engaging member movably mounted on the upwardly extending portion of the adjustable member and adapted to facilitate positioning of a piece of sheet metal on the brake at a desired location; a fine adjustment mechanism mounted on the upwardly extending portion of the adjustable member for moving the sheet metal-engaging member to a desired position; and a second securing mechanism for securing the sheet metal-engaging member at the desired position. 